Richard Blackden is the Telegraph's US Business Editor.

Occupying Wall Street from the inside

Mike Mayo has made errors. In the spring of 2007, he slapped a buy rating on Lehman Brothers. He didn't peel it off until September 11, 2008, by which time the bank was well past its sell-by date.

It's the sort of call that doesn't do much for the reputation of Wall Street analysts. It's also a fair assumption that Mayo has probably made a decent amount of money from a career spent telling investors whether to buy, hold or sell shares in US banks. After spending five years as a bank examiner at the Federal Reserve, Mayo's CV includes UBS, Credit Suisse, Lehman Brothers, Deutsche Bank and, now, CLSA, a brokerage part-owned by French bank Credit Agricole.

If any of that is inclined to put you off reading Exile on Wall Street – Mayo's account of his almost 20-year career tracking America's banking industry – don't let it. The exile in the book's title wasn't self-imposed, but refers instead to a series of scraps he's had with Wall Street banks that began in May 1999 when he hoisted a sell recommendation over all of the 47 lenders he then covered while working at Credit Suisse.

As is common practice, Mayo delivered the news to the Swiss bank's sales staff over a microphone, or "hoot" as it's sometimes known. Having returned to his desk, Mayo was asked to go back to the mic to explain to an incredulous audience why the recommendation had to be sell rather than simply hold. The call, of course, was unlikely to be helpful to his investment banking brethren at Credit Suisse who would be competing for any M&A work that was happening in the financial services industry.

The intense commercial pressure that ostensibly objective analysts face is one of a handful of central observations that Mayo makes. For anyone who has read what's now a small library of books on the causes of the financial crisis, his other observations will have a familiar, even tired, ring to them.

That until the crisis, regulators happily swallowed from banks a line that General Motors first trotted out in the 1950s: what's good for us, is good for America. That incentives at banks were dangerously skewed towards generating short-term results. That banks use all manner of accounting gimmicks to polish their results, making it harder for an accurate picture of their financial health to emerge.

The picture that Mayo paints of Wall Street is one in which little has fundamentally changed since the bankruptcy of Lehman Brothers. On the one hand, he says America's biggest banks remain too big to fail. On the other, the country's regulators lack the resources, and possibly the will, to implement a new rulebook that's too large anyway.

It's a worrying situation for the US taxpayer, the broader American economy and, in the long run, Wall Street too.

Exile on Wall Street doesn't offer any grand answers, though it's clear Mayo believes that it would be better if banks were shrunk to a size in which their failure could be handled without the taxpayer having to ride – reluctantly – to the rescue.

That Mayo doesn't spend chapters sketching out a new vision for Wall Street and the place of the financial services industry in American society is no bad thing. There are plenty of books that have done.

The answer, of sorts, that Mayo does offer is an insistence on pressing and probing the world's most powerful financial institutions for more information about their earnings, accounting and wider operations. That's led to dust ups with Jamie Dimon, the chief executive of JP Morgan Chase and, more recently, Vikram Pandit, the head of Citigroup.

Mayo says he had to intercept Pandit in the lobby of a building in order to nail down a meeting with him that he claims Citi were avoiding because they didn't like his questions. Mayo has clearly warmed to the role of exile. It has, after all, allowed him to write the book.

Mayo says he wanted to write a book in "plain English" about life as an analyst on Wall Street. Though Mayo says he's been surprised by the number of complimentary emails he's had from people working in financial services, the book is not going to be a bestseller.

But as a detailed and readable account of someone trying to hold Wall Street to higher standards of transparency and resisting its sharper practices while working on it, it's a refreshing antidote to the sometimes frustrating vagueness of the demands of the Occupy Wall Street movement.